package com.joney.common.utils;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;

/** 生成验证码 */
public final class SecurityCodeUtil {

    private static final Random RANDOM = new Random();

    /** 验证码库(英文) */
    private static final String WORD = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    /** 验证码库(数字) */
    private static final String NUMBER = "0123456789";
    /** 验证码库(中文) */
    private static final String CHINESE = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728" +
            "\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927" +
            "\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b" +
            "\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8" +
            "\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837" +
            "\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934" +
            "\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd" +
            "\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b" +
            "\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f" +
            "\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7" +
            "\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb" +
            "\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240" +
            "\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd" +
            "\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14" +
            "\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a" +
            "\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8" +
            "\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374" +
            "\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11" +
            "\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd" +
            "\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005" +
            "\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d" +
            "\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839" +
            "\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1" +
            "\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08" +
            "\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49" +
            "\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d" +
            "\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb" +
            "\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001" +
            "\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a" +
            "\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1" +
            "\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f" +
            "\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64" +
            "\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc" +
            "\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2" +
            "\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa" +
            "\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce" +
            "\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c" +
            "\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7" +
            "\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b" +
            "\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c" +
            "\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";

    /** 最小宽度 */
    private static final int LEAST_WIDTH = 100;
    /** 最小高度 */
    private static final int LEAST_HEIGHT = 30;
    /** 最少个数 */
    private static final int LEAST_COUNT = 4;
    /** 字体 */
    private static final String FONT_STYLE = "Monospace "; //Monospace Fixedsys

    /**
     * <pre>
     * 生成验证码图像对象
     *
     * SecurityCodeUtil.Code code = generateCode(count, style, width, height);
     *
     * // 往 session 里面丢值
     * session.setAttribute("xxx", code.getContent());
     *
     * // 向页面渲染图像
     * response.setDateHeader("Expires", 0);
     * response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
     * response.addHeader("Cache-Control", "post-check=0, pre-check=0");
     * response.setHeader("Pragma", "no-cache");
     * response.setContentType("image/jpeg");
     * javax.imageio.ImageIO.write(code.getImage(), "jpeg", response.getOutputStream());
     * </pre>
     *
     * @param count  验证码数字个数, 最少 4 个. 传空值或传小于 4 的值会使用最少值
     * @param style  图片上的文字: 英文, 数字(num), 英文加数字(n)还是中文(cn), 传空值或传的值不是 num n cn 则会默认是英文
     * @param width  生成的图片宽度, 最小 100. 传空值或传小于 100 的值会使用最小值
     * @param height 生成的图片高度, 最小 30. 传空值或传小于 30 的值会使用最小值
     * @return 图像
     */
    public static Code generateCode(String count, String style, String width, String height) {
        int loop = toInt(count);
        if (loop < LEAST_COUNT) loop = LEAST_COUNT;

        String str = WORD;
        if ("num".equalsIgnoreCase(style))
            str = NUMBER;
        else if ("n".equalsIgnoreCase(style))
            str += NUMBER;
        else if ("cn".equalsIgnoreCase(style))
            str = CHINESE;

        int widthCount = toInt(width);
        if (widthCount < LEAST_WIDTH) widthCount = LEAST_WIDTH;

        int heightCount = toInt(height);
        if (heightCount < LEAST_HEIGHT) heightCount = LEAST_HEIGHT;

        // ========== 上面处理参数的默认值 ==========

        BufferedImage buffImg = new BufferedImage(widthCount, heightCount, BufferedImage.TYPE_INT_RGB);
        Graphics graphics = buffImg.createGraphics();
        // 图像背景填充为灰色
        graphics.setColor(Color.LIGHT_GRAY);
        graphics.fillRect(0, 0, widthCount, heightCount);
        // 边框填充为黑色
        graphics.setColor(Color.BLACK);
        graphics.drawRect(0, 0, widthCount - 1, heightCount - 1);

        // 画一些干扰线
        for (int i = 0; i < 32; i++) {
            graphics.setColor(new Color(RANDOM.nextInt(255), RANDOM.nextInt(255), RANDOM.nextInt(255)));
            graphics.drawLine(RANDOM.nextInt(widthCount), RANDOM.nextInt(heightCount),
                    RANDOM.nextInt(widthCount), RANDOM.nextInt(heightCount));
        }

        graphics.setColor(Color.BLUE);
        // 字体大小看输出的图片高度
        graphics.setFont(new Font(FONT_STYLE, Font.PLAIN, heightCount - 10));

        int x = (widthCount - 4) / (loop + 1);
        int y = heightCount - 7;

        StringBuilder sbd = new StringBuilder();
        for (int i = 0; i < loop; i++) {
            String value = String.valueOf(str.charAt(RANDOM.nextInt(str.length())));
            graphics.drawString(value, i * x+10, y);
            sbd.append(value);
        }
        return new Code(sbd.toString(), buffImg);
    }

    public static int toInt(String str) {
        if (str == null) return 0;

        try {
            return Integer.parseInt(str);
        } catch (NumberFormatException nfe) {
            return 0;
        }
    }

    @Getter
    @Setter
    @AllArgsConstructor
    @NoArgsConstructor
    public static class Code {
        private String content;
        private BufferedImage image;
    }
}
